Uma nova proposta de fluidos de perfuração aquosos à base de polímeros vinílicos e bentonita para poços de alta temperatura e pressão

The advance of drilling in deeper wells has required more thermostable materials. The use of synthetic fluids, which usually have a good chemical stability, faces the environmental constraints, besides it usually generate more discharge and require a costly disposal treatment of drilled cuttings, which are often not efficient and require mechanical components that hinder the operation. The adoption of aqueous fluids generally involves the use of chrome lignosulfonate, used as dispersant, which provides stability on rheological properties and fluid loss under high temperatures and pressures (HTHP). However, due to the environmental impact associated with the use of chrome compounds, the drilling industry needs alternatives that maintain the integrity of the property and ensure success of the operation in view of the strong influence of temperature on the viscosity of aqueous fluids and polymers used in these type fluids, often polysaccharides, passives of hydrolysis and biological degradation. Therefore, vinyl polymers were selected for this study because they have predominantly carbon chain and, in particular, polyvinylpyrrolidone (PVP) for resisting higher temperatures and partially hydrolyzed polyacrylamide (PHPA) and clay by increasing the system's viscosity. Moreover, the absence of acetal bonds reduces the sensitivity to attacks by bacteria. In order to develop an aqueous drilling fluid system for HTHP applications using PVP, HPAM and clay, as main constituents, fluid formulations were prepared and determined its rheological properties using rotary viscometer of the Fann, and volume filtrate obtained by filtration HTHP following the standard API 13B-2. The new fluid system using polyvinylpyrrolidone (PVP) with high molar weight had higher viscosities, gels and yield strength, due to the effect of flocculating clay. On the other hand, the low molecular weight PVP contributed to the formation of disperse systems with lower values in the rheological properties and fluid loss. Both systems are characterized by thermal stability gain up to around 120 ° C, keeping stable rheological parameters. The results were further corroborated through linear clay swelling tests.

Análises estruturais e atividades biológicas de exopolissacarídeo extraído do fungo comestível pleurotus Sajor-Caju e de seu derivado sulfatado quimicamente.

The exopolysaccharides are extracellular compounds produced by some species of fungi and bacteria. It is suggested that these molecules, even when in the form of complex polysaccharide-peptide, are the main bioactive molecules of many fungus. Some of the biological activities displayed by these compounds can be accentuated and others may arise when you add chemically polar or nonpolar groups to polysaccharides. The fruiting body of Pleurotus sajor-caju produces a heteropolysaccharide with antineoplastic and antimicrobial activity, but other biological activities of this polymer have not been evaluated. In this work the exopolysaccharide of Pleurotus sajor-caju was sulfated chemically and structurally characterized. We also evaluated the antiproliferative, antioxidant and anticoagulant activities from native exopolysaccharide (PN) and its sulfated derivated (PS). Polyacrylamide gel electrophoresis, infrared spectroscopy and nuclear magnetic resonance (¹³C) proved successful in sulfation of PN to obtain PS. Analysis by gas chromatography-mass spectroscopy showed that PN and PS are composed of mannose, galactose, 3-O-methyl-galactose and glucose in proportion percentage of 44,9:16,3:19,8:19 and 49, 7:14,4:17,7:18,2, respectively. The percentage of sulfate found in PS was 22.5%. Antioxidants assays revealed that the sulfation procedure affects differently the activities of exopolysaccharides, while the total antioxidant capacity, the scavenging activity of superoxide radical and ferric chelating were not affected by sulfation, on the other hand the chemical modification of PN enhanced the scavenging activity of hydroxyl radical and reducing power. PS also showed anticoagulant activity in a dose-dependent manner and clotting time was 3.0 times higher than the baseline value in APTT at 2 mg/mL. The exopolysaccharide not presented antiproliferative activity against HeLa tumor cells, but PS affects the cellular proliferation in a time-dependent manner. After 72 h, the inhibition rate of PS (2.0 mg/mL) on HeLa cells was about 60%. The results showed that PN sulfation increase some of their activities.

Prevalência da infecção por HPV e perfil das mulheres frente ao exame de papanicolau no município de São José de Mipibú/RN.

The Human Papillomavirus (HPV) infection is the major sexually transmitted disease all over the world. There are many factors associated to infection and the virus persistency in the organism. This study aims to evaluate the women's knowledge, attitudes and practice about the Papanicolaou test (Pap), as well as analyze the HPV and Chlamydia trachomatis infections prevalences in sexually active women from the city of São José do Mipibu/RN/Brazil. This research was divided in two steps (step I and step II), using different methodologies and samples each. The samples collected in each step, even socio-demographic or from uterus cervix, are from different patients e were analyzed separated. In step I was evaluated 267 rural and urban zone women s knowledge, attitudes and practices about the Pap by home interview. In the step II were included 605 women with age ranged from 15 to 71 years old, with mean of 33,5 years old and from each one were collected two cervical samples, one for Pap and other for molecular biology, beside the epidemiological interview to investigate the correlation between prevalence of HPV infection and risk factors. To molecular analyses, the samples were processed using a mammal rapid DNA extraction technique protocol. For C. trachomatis DNA detection were used the CP24/27 primers, and GP5+/GP6+ to HPV. PCR products were analyzed by electrophoresis on 8% polyacrylamide gels, followed by silver staining. The results of the step I showed that, in spite of only 46,1% of the interviewed women they have demonstrated to possess appropriate knowledge on the Pap test, the attitude and practice proportions were significantly larger, 63,3% and 64,4% respectively. The largest education degree presented association with adaptation of the knowledge, attitudes and practice, while neglect, lack of solicitation of the exam for the doctor and shame, came as main barriers for the accomplishment of the exam. In the stage II the HPV general prevalence was 28,9%, being 26,7% in the women with normal cytology or benign alterations, 26,7% in the ones that had atypical squamous cells of undetermined significance (ASC-US) and 80% in those with Low grade squamous intraepithelial lesion (LSIL). the HPV infection prevalence was larger in the patients with up to 30 years of age and in the unmarried women, and those that had more than one sexual partner presented larger infection risk. The results show that the sexual relationship with multiple partners increased the infection risk for HPV and consequently the possibility of the occurrence of lesions uterine cervix